Formulas
PostScript / DTP:
1 in = 72 pt
1 pica = 12 pt
So: 1 in = 72 ÷ 12 = 6 picas
picas = inches × 6
points = inches × 72
PostScript vs ATA (traditional)
Older US printing sometimes used 1 in = 72.27 pt (the “American Type Founders” point). If you have an old layout or a book that specifies 12 picas = 72.27 pt, pick the second option — it will give you slightly different pica/point values.
FAQ
1. Do web and CSS use picas?
Not commonly. Web layouts usually use px, rem, em, or occasionally pt. Picas/points are still common in InDesign, Illustrator, and print production.
2. Can I convert 8.5 × 11 in (Letter) to picas?
Yes: 8.5 in × 6 = 51 picas wide; 11 in × 6 = 66 picas tall (PostScript system).
3. Which one should I choose if I’m unsure?
Choose “PostScript / DTP.” It’s what modern layout software uses, and it’s the one most online converters expect.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
PostScript / DTP: 1 in = 72 pt 1 pica = 12 pt So: 1 in = 72 ÷ 12 = 6 picas picas = inches × 6 points = inches × 72
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures - NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.